The ongoing emergence of the use of optical means for collecting, transmitting and processing information emphasizes an acute need for a reliable and accurate calibration of components for effective information transfer. The accurate calibration of a wide variety of optical sensors must precede their applications so that meaningful data can be collected.
Historically, such sensors usually are calibrated at a fixed and permanent manufacturing facility or in a centralized calibration laboratory. This may mean that some time may pass before their ultimate deployment, irrespective that time, intervening events and ambient exposures might alter some components' responses prior to use.
At least one conventional calibration approach using curtains attempted to prevent unneeded and unwanted radiant energy from reaching the sensors under calibration. The bulky, opaque black curtains and adjustable baffles were placed around a reference source which irradiated the sensors undergoing calibration and test. The opaque curtains were heavy to provide light containment and to eliminate extraneous light reflection paths caused by the walls, floor, ceiling and other neighborhood objects. The curtains also were needed to block direct vision paths to protect the workers' eyes. Although the potentially unsafe direct vision paths were reduced, sometimes the curtain structure allowed for numerous unforeseen paths of opportunity for unwanted exposure due to the displacable geometry of the curtain arrangement. Furthermore, associated curtain supporting structure, such as, hangers, rails, ropes and hooks were needed which allowed worker access to the calibration elements. All this paraphernalia restricted worker movement. Thus, the technique, while arguably being effective, imposed the disadvantages of bulk, restriction of worker movement and the ever-present danger of exposing the worker's eye's to the intense tungsten filament lamp output (up to 1000 watts).
Thus, a continuing need exists in the state of the art for a man-portable device that eliminates curtains and the associated paraphernalia to increase worker safety by reducing the possibility of direct vision paths to an intense calibration light while attaining a desired suppression of stray light and increased worker accessibility to enable a more accurate calibration.